Generally speaking printing radio frequency identification (RFID) tags on media labels requires a RFID programming module or an RFID reader with a RFID antenna to transmit signals to program the tag on the media label.
When programming RFID tags on or in a media label, the RFID antenna is placed as close as possible to the platen roller and the print head burn line in order to support the tag. Due to the structure of conventional printers and the need to be as close as possible to the print head burn line, the RFID antenna is usually placed below the media path and is positioned 18 to 34 mm from the print head burn line. However, it is difficult if not impossible for the RFID antenna to support metal RFID tags on or in the media label if the RFID antenna is positioned below the media because of layers on the tag which may block RFID signals from below. The metal RFID tag generally is made of layers. The top layer is the IC layer where the programmable chip resides. This chip needs to receive transmitted power from the RFID antenna for programming. Below the IC layer is an aluminum foil layer which will generally partially or completely block the RFID frequency. If placed above the media path on a conventional printer, the RFID antenna would necessarily be at least 70 mm from the print head burn line. This is too great a distance for the RFID antenna to support a metal tag on the media label.
In addition, for good print registration, a label stop sensor (LSS) module should be close to the print head burn line. In a conventional printer, the LSS module may be as far away as 42 to 55 mm from the print head burn line whether the RFID antenna is above or below the media path. In either case, print registration could be improved significantly if the LSS module could be placed closer to the burn line.
Prior art FIG. 1 shows in schematic a conventional printing assembly, illustrating the position and limitations of conventional printer structures. The printing assembly (10) includes a print head (90), platen roller (15), the RFID antenna (14), and a LSS module (18), with the burn line designated at (13). The printer ribbon path (16) and the media path (17) are designated. In the FIG. 1, the RFID antenna (14) would have to be moved a considerable distance from the burn line (15) to accommodate the RFID antenna (14) above the media path (13). This requires the LSS module (18) to be positioned even further from the burn line (13). Both the print head (12) size and orientation as well as the ribbon path (16) constrains the placement of the RFID antenna (14).
Therefore, a need exists for a printer system and method which allows a RFID antenna to conveniently support metal RFID tags on media labels while simultaneously providing for improved print registration.